Backfire release



M. P. WHITNEY Nov. 6, 1934.

BACKFIRE RELEASE {File d. Nov. 50, 1951 INVENTOR A TTORNEY Patented Nov. 6, 1934 PATENT OFFICE BACKFIBE RELEASE Maurice P. Whitney,- Elmira, N. Y., assignor to Eclipse Machine Company, Elmira, N. Y., a corporation of New York Application November 30, 1931, Serial No. 578,117 12 Claims; (c1. 290-38) This invention relates to back-fire releases and more particularly to a device for preventing actuation of a starting mechanism for internal combustion engines while said engine is rotating backward.

In automatic starting mechanism for internal combustion engines it is important to \provide means to prevent the automatic actuation of the starting mechanism when the engine is rotating backward since such untimely engagement of the starting mechanism throws severe stresses thereon.

It is an object of the present invention to provide a novel device for preventing actuation of an automatic starting mechanism for internal combustion engines while the engine is rotating backward.

It is another object of the invention to provide such a device which restores the automatic starting mechanism to operative condition when the backward rotation of the engine ceases.

It is a further object to provide such a device which is arranged to cause a predetermined time delay after backward rotation .01 the engine 35 ceases before. the reactuaticn of the starting mechanism.

Another object is to provide such a device which utilizes the elements of a commercial form of automatic starting mechanism to perform the functions desired under the control of an auxiliary device oi. simple, economical construction. Further objects and advantages will be apparent to those skilled in this art from the following description taken in connection with the accompanying drawing in which the figure is a semi-diagrammatic showing of a preierred'embodiment of the invention, the parts of theauxiliary controlling device being shown in section;

In the drawing, there is illustrated an el'ectri-- cal "starting system for an'intemal combustionengine, not shown, comprising a battery 1 rounded at 2 and connected by a lead 3 to a commercial form of automatic starting mechanism indicated generally by numeral 4. The

automatic starting mechanism comprises a starting switch 5 which is connected to the battery lead 3 and is connected by a single turn coil6 and a lead 7 to the starting motor SM which is grounded at 81to complete the starting circuit.

5 Starting switch 5 is arranged'to be magnetically operated by means of a solenoid 9 which is energized by a control circuit including a battery lead 11, ignition switch 12, leads 13 and 14, fixed contact 15 and movable contact 16- on spring strip 1'7 which is grounded at 18.

Contact 16 is normally maintained in engagement with fixed contact 15 by the spring strip 17, but is adapted to be moved out of such engagement by means of a lever 19 which is adapted to engage a weight member 21 on the end of the spring strip 17 when the lever is moved downwardly by a solenoid plunger 22. Solenoid plunger 22 is normally maintained in its upper position as by means of a spring 23 but is adapted to be attracted downwardly by a shunt coil 24. Coil 24 is arranged to be energized from the battery 1 when the starting switch 5 is closed, by means of a circuit including a lead 25 connected to motor lead 7, a lead 26 and ground connection 27. Plunger 22 is maintained in its retracted position during normal operation of the engine by a generator coil 28 which is connected at one end by a lead 29 to the generator G and is grounded at its other end at 27. Shunt coil 24 therefore constitutes means for opening contacts 15, 16 while generator coil 28 constitutes means for holding said contacts open during normal operationof the engine.

According to the present invention, means are provided for energizing the shunt coil 24 from 0 the battery 1 to maintain contacts 15, 16 open during rearward rotation of the engine at which time the generator G would be ineffective to energize coil 28 to hold said contacts open. As here shown, this structure comprises a device responsive to pressure in the intake system of the engine to disconnect the shunt coil 24 from the starting switch lead 7 and to connect the same to the lead 13 of the control circuit. In the embodiment shown, an elastic diaphragm 31 is mounted in an air-tight case 32 which is provided with an inlet 33- threaded into an element 34 of the engine fuel intake system such as the intake. manifold. Diaphragm 31 carries a centrally located pin 35 which is arranged to control a set of contacts 36, 37, 38 and 39. Contact 36 is connected to lead 25, contacts37 and 38 are mounted on a spring strip 41 which is connected to lead 26 of the shunt coil, while contact 39 is connected by a lead 42 to the com trol circuit lead 13.

The arrangement of contacts 36, 37, 38, 39 is such that when the diaphragm 31 is subjected to atmospheric pressure or vacuum within the intake manifold, contacts 36 and 37 are closed and the shunt coil is connected as usual to the starting switch 5 to be energized when said switch is closed. When pressures are generated in the intake manifold, however, ,by the backward rotation of the engine such as in upward to open contacts 36, 3'7 and close contacts 38, 39. This causes the shunt coil 24 to be energized from the control circuit lead 13 whereby the lever 19 is moved to open contacts 15,16 and hold 'said contacts open as-long as the pressure persists in the intake manifold.

In the operation of the device, starting with the parts in the positions illustrated, closure of ignition switch 12 completes the control circuit causing solenoid 9 to close starting switch 5 and actuate the starting motor. At this time shunt coil 24 is energized by current traversing leads 25 and 26, but plunger 22 is held in its upperposition by the magnetic flux of the single turn coil 6 as it is traversed by the heavy current energizing the starting motor. When the engine starts. and the motor SM spins freely, the reduction of current through the coil 6 per mits the shunt coil 24 to move the plunger 22 downwardly, causing lever 19 to open contacts 15, 16, thus deenergizing solenoid 9 and allowing the starting switch 5 to open. Plunger 22 strip 17 comes to rest, the starting operation is repeated.

If, after'actuation of the starting mechanism the engine should back-fire causing rearward rotation thereof, pressure is generated in the intake manifold 34 by such rearward; rotation of the engine which causes diaphragm 31 to open contacts 36, 37 and close contacts 38, 39. A circuit is thereby completed through ignition switch 12, control circuit, lead 13, lead 42', spring strip 41 and lead 26 to the shunt coil 24, returning through the ground connection 2'? whereby the shunt coil is energized to actuate plunger 22 to open contacts 15, 16. The control circuit for solenoid 9 is thus maintained open, as long as the engine is rotating backward. When backward rotation ceases, contacts 38, 39 are broken. deenergizing the shunt coil 24 and releasing plunger 22. Reclosing of the starting switch 5 is delayed in this, case in the same manner as in case of forward rotation of the engine as previously described namely by means of the vibration of spring strip 17, whereby the engine is allowed to come completely to rest prior to reactuation thereof.

Although but one embodiment of the invention has been shown and described in detail, it will be understood that various other embodiments are possible and changes may be made in the details of construction and arrangements of the parts without departing from the spirit of the invention as defined in the claims appended hereto.

What is claimed 'is:

1. In automatic starting mechanism for internal combustion engines, starting mechanism including a starting switch, a control circuit therefor including magnetic operating means for the starting switch, means for opening the con-- trol circuit when the engine starts, means for case of back-fire, diaphragm 31 will be moved energizing said opening means when the engine rotates backward, and means for delaying closure of the control circuit until a predetermined.

time after the backward rotation of the engine has stopped.

2. In automatic starting mechanism for internal combustion engines, starting mechanism including a starting switch, a control circuit therefor including magnetic operating means for the starting switch, opening means for the control circuit, means for actuating said opening means when the engine starts, means for actuating said opening means when the engine rotates backward and means for delaying effective closure of the control circuit until a predetermined time after deenergization of the opening means.

3. Automatic starting mechanism for internal combustion engines including a magnetically operated starting switch, a control circuit therefor, means for opening said control circuit when the engine starts, means for holding said circuit open as; long as the engine rotates forwardly, means for delaying effective closure of the control circuit until a predetermined time after forward rotation of the engine ceases, and means for energizing the opening means to open the control circuit when the engine rotates backward and to hold it open until backward rotation stops, said time delay means being effective to delay closure of the control circuit after such backward rotation ceases.

4. In combination, an internal combustion engine including a fuel intake system, automatic starting mechanism for said engine including a magnetically operated starting switch, a control circuit therefor, magnetic means for opening, said control circuit when the engine starts and means responsive to positive pressure in the intake system of saidengine above atmospheric pressure for energizing said opening means.

5. .In combination, an internal combustion engine including a fuel intake system, automatic starting mechanism for said engine including a magnetically operated starting switch, a con-.

time after the deenergization of said opening means.

' 6. In combination, an internal combustion engine including-a fuel intake system, automatic starting mechanism for said engine including a starting motor and a magnetically operated starting switch, a controlcircuit therefor, magnetic means energized by closure of the starting switch for opening said control circuit when the engine starts, means for maintaining the energization of said magnetic means after-the starting switch opens during the spinning of the starting motor by momentum, and means responsive'to pressure in the intake system of the engine for energizing said magnetic means during backward rotation of said engine.

'7. In combination, an internal combustion engine including a fuel intake system, automatic starting mechanism for said engine including a magnetically operated starting switch, a control circuit therefor including a pair of contacts, a solenoid energized by closure of the starting switch for opening said tontacts when the engine starts, and means responsive to pressure in the intake system of the engine for breaking the connection of said solenoid to the starting switch and causing energization of said solenoid during backward rotation of the engine.

8. In an automatic starting mechanism for internal combustion engines a magnetic starting switch, a control circuit for said switch including a make and break device, means responsive to self-operation of the engine for holding said make and break device open, means responsive to backward rotation of the engine for holding said make and break device open, and means effective upon the release of said make and break device to vibrate the same .a predetermined time before efl'ective closure thereof.

9. In an automatic starting mechanism for internal combustion engines a magnetic starting switch, a control circuit for said switch including a make and break device, means responsive to backward rotation of the engine for opening said make and break device, and means efi'ective upon the release of said make and break device to vibrate the same a predetermined timebefore effective closure thereof.

10. In combination with an internal combustion engine having a fuel intake system, a starter control for said engine including a magnetic starting switch, a control circuit for said switch including a make and break device, means responsive to positive pressure above atmospheric pressure in said fuelintake system for opening said make and break device, and means for vibrating said make and break device a predetermined time after release thereof before effective closure thereof.

11. In combination with an internal combustion engine having a fuel intake system, a starter control for said engine including a magnetic starting switch, a control circuit for said switch including a make and break device, a pressure responsive device including an element movable by variation in pressure above atmospheric pressure in the fuel intake system, means whereby movement of the pressure responsive device responsive to such pressure variations causes said make and break device to be opened, and means for vibrating said make and break device a predetermined time before allowing effective closure thereof.

12. In combination with an internal combustion engine having a fuel intake system, a starter control for said engine including a magnetic starting switch, a control circuit for said switch including a make and break device, a pressure responsive device including an element movable by variation in pressure above atmospheric pressure in the fuel intake system, means whereby movement of the pressure responsive device responsive to such pressure variations causes said make and break device to be opened, said make and break device including a pendulously mounted contact biased to closed position, and means for causing vibration of said contact for a predetermined time after release thereof.

MAURICE P. WHITNEY. 

